Abstract

The Sicilian tectonic edifice is a segment of the Apenninic-Maghrebian Chain, which results from the Neogene deformation of the Africa passive continental margin. The Sicilian orogen is made of a set of tectonic units; the more inner and highest are located in north-eastern Sicily (Peloritani and Sicilidi units) and thrust over the more external Sicilian-Maghrebides units outcropping in central-western Sicily. The tectonic units result from the deformation of rock successions deposited on adjacent Mesozoic palaeogeographic domains which, from the present-day external sectors of the orogen, was represented by a wide carbonate platform (Hyblean-Pelagian Domain), a wide pelagic basin (Imerese-Sicanian Domain) flanked by the carbonate platform of the Panormide Domain. The Panormide carbonate platform had a smaller extent respect to the Hyblean-Pelagian Domain and becomes more and more restricted in the late Jurassic, as a consequence of the "opening" of the Sicilide Basin which completely separated the Austroalpine sector from the Panormide domain. The Mesozoic physiography of the Sicilian Maghrebides controls the later development of the Neogene collisional systems: the location and the width of the Imerese-Sicanian and Sicilide Domains (and their lithospheric thickness) control the development of the Neogene foredeep and of several facies characteristics of the syntectonic successions. The lithospheric thickness of the Hyblean-Pelagian Block also controls the development and propagation of thrust tectonics in the Sicilian Maghrebides. In this way, the definition of the geometrical relationships between the tectonic units and the coeval syntectonic deposits, and their stratigraphical characteristics, let us to reconstruct the evolution of the "chain front-foredeep-foreland system" during Miocene-Pleistocene times, through the chronology of the deformational events. The main tectono-sedimentary stages of the Sicilian foredeep are described, focussing on the late Oligocene-early Miocene, Langhian-middle Tortonian, late Tortonian-early Messinian, late Messinian and Plio-Pleistocene times. During these intervals the internal flank of the Sicilian foredeep is progressively made of more and more external deforming sectors (from the Peloritani to the Imeresi-Sicanian and Hyblean-Pelagian p.p.), through the progressive migration of the kinematic front, which is today located in the southern Sicily offshore and, on land, along the Gela-Catania alignment.